U.S. Pat. No. 5,232,051 describes a continuous oil-only recovery apparatus for recovering oil from mature, low production wells that are normally abandoned once further oil production becomes uneconomical. The oil-only recovery apparatus pulls a continuous conveyer chain suspended in a well borehole through the oil stratum to draw oil from the stratum and deposit the collected oil in a reservoir. Capillary, electrical or chemical attraction causes the oil to attach to the links of the chain. The oil laden chain is pulled to the surface where the oil is removed from the chain for collection by a scouring mechanism, referred to as a scrubber.
The continuous conveyer chain mechanism has proven to be a highly efficient means for drawing crude oil from mature, low production wells; however, the scouring mechanisms used to remove the oil from the conveyer chain, heretofore, have not been efficient enough to make the use of oil-only recovery apparatus practical or economical for well operators. The problem being that the conventional scouring mechanism or scrubbers fail to remove sufficient quantities of oil at chain speeds that were optimal for drawing sufficient quantities of oil to the surface. Scrubbers have used various mechanical means, including steel wool, brushes, scrapers, wipers and the like, which physically brush and scrape the attached oil from the links of the conveyer chain. A casing packed with steel wool through which the oil-laden conveyer chain passed has, heretofore, been the most successful scouring mechanism. The steel wool within the casing physically scrapes, brushes and scours the oil from the links. Typically, these scrubbers fail to make sufficient contact with the chain to remove enough oil to be commercially viable. The physical scouring components, whether steel wool, brushes, scrapers or wipers of any type, quickly become saturated with oil and lose any degree of effectiveness that they may have had in removing the oil from the conveyer chain. Consequently, much of the crude oil drawn from the well was not removed from the chain, and therefore returned back into the well with the conveyer chain. In order to make continuous oil-only recovery apparatus commercially viable, practical and economically efficient scrubbers are needed.